My Acer XR341CK has a feature to always display refresh rate in a corner.
Refresh rate syncs with FPS reported by game up the the point you pick a hero, but while in a match, it is stuck at 75Hz, while FPS reported by the game fluctuates between 72-75. My frame cap is set to 75, since at first i thought it was because of the refresh rate+10 cap.
Graphics card is XFX RX480 LED V1 (not Black Edition), Freesync is enabled in AMD software and the status light of the monitor changes when game is open.
Same/similar thing happens in HOTS - while in match, game reports 60-70fps but refresh barely fluctuates from 75. Out of fame it syncs fine.